Honing is not really necessary. The sealing occurs between the surface of the pistons and the O ring. The critical areas on the calipers are the grooves for the O rings and the seal seat pockets. Clean these extremely well. I use small wire brushes, steel wool, a dentist's pick (to get into the edges of the O ring seal) and paint thinner/mineral spirits. I do the final wash using hot, soapy water, rinse with clean water and blow dry it using compressed air.

Many people use BrakeKleen or its ilk and have good success. I'm not a proponent of the nasty crap but it's your car, lungs and money.

The piston is the main component. 90% of them can be cleaned and re-used with no problems. The thing you need to watch for is rust which has penetrated the polished surface of the "drum". Rust around the top of the piston, inside the cavity and the bottom edge is common and is of no concern as these can easily be cleaned and are not part of the sealing surfaces. Do NOT use a steel brush on the polished areas of the pistons.

Re-assembly can be a finicky procedure. Insert the O rings, ensure they are seated fully into the grooves of the caliper, lube them with brake fluid, lube the piston and evenly work the piston into the caliper. You'll need to move around the rim of the piston to get it to slide into place. Do not force it or use a vise. Compress the piston about 2/3 rds of the way down and fit the dust boot over the piston and into the receiving area of the caliper housing.

Repeat 3 more times for the remaining pistons or take Tubber's advice and avoid the aggravation.

Yes, the idea of replacing in axle pairs is to ensure you have even pressure/operation.

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now